Originally Posted by ramki067
Can I know why? It's just for my knowledge.
The main reason is because OEM Roms (specifically Touchwiz, Sense, Xperia UI) require heavily on OEM specific hardware, framework and kernel to function correctly.
Those OEM roms are closed source and without them, it will be very difficult for developers to write compatible driver, kernels (that function in conjunction with framework) to other samsung phones; yet alone a phone from a different manufacture.
In that regard, if a rom was ported over, the only functioning thing would probably be the touchscreen and nothing else.